Known outdoor electrical boxes for providing electrical connection points for outdoor power access include wall-mounted receptacles and post-mounted receptacles that may be mounted on vertical surfaces, and electrical boxes mounted in the ground or other horizontal outdoor surface for providing electrical connection points distant from existing walls. For example, in an athletic field, a large public flower garden, or a public park, it may be desirable to provide electrical receptacles for intermittent electrical connections, such as short-term lighting, power washers, and electric maintenance equipment, e.g., hedge trimmers and chain saws. The electrical connection points must be accessible so that a user can plug and unplug devices as required.
Moisture is a significant problem for outdoor electrical boxes because it may lead to electrical box failure and/or may result in a serious electrocution risk. Moisture is particularly problematic for electrical boxes installed in the ground because water may collect and pool therein. Therefore, when electrical power fed into an outdoor electrical box from a power source, for example through a power line buried underground, the power line is led into a NEMA Type 6 enclosure, which is designed to be impenetrable to water during occasional submersions in water. NEMA stands for National Electrical Manufacturer's Association. From the NEMA Type 6 enclosure, power may then be routed to electrical connection points, such as receptacles, within the electrical box, where the electrical box is typically designed in such a way to keep water from reaching the faces of the electrical receptacles and/or the electrical connection points.
However, even though the NEMA Type 6 enclosure is designed to be impenetrable to water, if the enclosure is left submerged for an extended period of time, air may be able to slowly escape the enclosure through the cord or cords that exit the enclosure and connect to the electrical connection points, thereby allowing the NEMA Type 6 enclosure to fill with water.